WO2019062398A1 - Method and apparatus for seamlessly switching 50hz-60hz and 50hz-50hz dual-frequency shore power to ship power - Google Patents

Abstract

Disclosed are a method and apparatus for seamlessly switching 50Hz-60Hz and 50Hz-50Hz dual-frequency shore power to ship power. Upon power supply switching between shore power and ship power, there is no need for equipment on a ship to be powered off; a following frequency f is controlled through V/f; next, through P/Q control, a load power is transferred from a ship power generator to a shore-power power grid to complete seamless switching; in addition, a shore power 50Hz power supply can supply power for a ship with two different power grid standards of 60Hz or 50Hz; when the ship of 50Hz is seamlessly connected to the shore power, a traditional synchronous meter or current-limiting control is not needed; instead, a 60Hz rectifying inverter is used as a 50Hz seamless and smooth transition apparatus for connecting the shore power; and after switching is completed, the rectifying inverter is switched off, and power is directly supplied by converting from a 50Hz inversion power supply to a shore power transformer, so that the smooth connection of an impact-free current is realized.

Description

Method and device for seamlessly switching ship power of 50Hz-60Hz and 50Hz-50Hz dual-frequency shore power Technical field

The invention relates to a method and a device for switching a ship power grid by a shore power supply, in particular to a method and a device for seamlessly switching a ship power of a dual frequency shore power.

Background technique

Ship shore power technology refers to the ship accessing the power grid at the dock side during the port period, and obtaining the power required for its water pump, communication, ventilation, lighting and other facilities from the shore power source, thereby shutting down its own diesel generator. After the ship is connected to the shore, it can effectively reduce the emission of exhaust gas. It has the significant advantages of energy saving and environmental protection. It can reduce the noise pollution caused by the operation of the generator set and reduce the cost. Therefore, the government and its transportation departments, shipping companies and port enterprises have vigorously promoted shore power. usage of.

The shortcoming of the existing shore power system is that most of the terminal power installations in China use 400V/50Hz power supply, and most of the ships that use the electric system are not willing to receive shore power because the general step of connecting the shore power is to close the ship first. The generator is connected to the shore power grid. When the ship needs to leave, the bank power grid is disconnected and the ship generator is started. The two power-off switching processes are extremely time-consuming, and many equipments on the ship are reset after the power is cut off. It takes 6 hours to reset the equipment after the power is cut off, which affects the sailing of the ship. In addition, there is a danger that the equipment will be started at the same time after the equipment is powered off. According to the investigation of the captain/engineer of the ocean-going vessel, if the vessel has a berthing time of 48 hours, it is generally unwilling to accept shore power. In addition, there are differences in power grid standards between shore power and ship power. According to the statistics of the International Maritime Organization, more than 60% of international shipping ships use 460V/60Hz electric system, while more than 60% of shore power supply is 400V/50Hz electric system. Ship power station and generator control are very different. It has created a great technical problem for the seamless connection of 50Hz shore power to 60Hz ship power.

Summary of the invention

Based on this, an object of the present invention is to provide a method capable of seamlessly switching ship power between 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power.

The technical solution adopted by the invention is:

A method for seamlessly switching ship power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power, characterized in that the method comprises the following steps:

Step 1: Connect the shore power grid lines including the shore power transformer and the rectifier inverter to the shore power source and the ship grid respectively, and select the shore power grid line as a 50 Hz or 60 Hz line according to the ship grid standard;

Step 2: The inner loop control method and the outer loop control method are adopted for the rectifier inverter, wherein the outer loop control method adopts the V/f control method, and the target frequency of the ship generator is converted into the target frequency of the shore power transformer output; Using a phase-locked loop control method to control the frequency and voltage of the rectifier inverter output;

Step 3: Convert the outer loop control method of the rectifier inverter from the V/f control method to the P/Q control method, control the ship generator frequency and voltage, and use the ship grid real-time load power as the target power to perform power transfer. The output power of the rectifier inverter increases, and the output power of the ship generator decreases; meanwhile, the phase-locked loop control method is used to control the frequency and voltage of the rectifier inverter output;

Step 4: When the ship generator output power drops to the preset power, the ship generator is turned off.

The method and device for seamlessly switching ship power of 50Hz-60Hz and 50Hz-50Hz dual-frequency shore power according to the present invention, when the shore power and the ship power supply are switched, the shipboard equipment does not need to be powered off, and the frequency f is controlled by V/f control, and then Through P/Q control, the load power is transferred from the ship generator to the shore power grid to complete seamless switching. In addition, the shore power 50Hz power supply can be realized, and the ships of different grid standards of 60Hz or 50Hz can be powered to adapt to different ships. Need.

Further, the shore power grid line includes a shore power transformer, a rectification inverter, a 50 Hz line, a 60 Hz line, and a public line, and the 50 Hz line includes a first switch, a second switch, a first inductor, a second inductor, and a a fourth inductor, a third inductor, a third inductor, a fifth inductor, and a second capacitor, the common line including a first resistor, a sixth inductor, and a fourth switch;

One end of the shore power transformer is used to connect the shore power source, the other end is connected to one end of the rectifier inverter and the first switch, and the other end of the rectifier inverter is respectively connected to one end of the second switch and the third switch; the other end of the first switch Connecting the first inductor to the other end of the second switch, the other end of the second switch is connected to the first connection end of the second inductor, and the second connection end of the second inductor is connected in series with the fourth inductor, the first resistor, a sixth inductor and a fourth switch are connected to the ship grid through the fourth switch, one end of the first capacitor is connected between the second inductor and the fourth inductor, and the other end is grounded; the other end of the third switch is connected to the third a first connection end of the inductor, a second connection end of the third inductor is sequentially connected in series with one ends of the fifth inductor, the first resistor, the sixth inductor and the fourth switch, and one end of the second capacitor is connected to the third inductor and the fifth inductor Between the other end of it is grounded.

Further, step 2 specifically includes the following steps:

Step 21: Obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate a dq axis component i _1d , i _{1q thereof} ; obtain a fourth inductance and a rectified inverter output voltage value v, a current value i ₂ between the first resistors and between the fifth inductor and the first resistor, wherein the voltage v includes its abc axis components v _a , v _b , v _c , and the calculation current The dq axis components i _2d , i _{2q of the} value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

Step 22: According to ω, u _ref , v _d , v _q , the current loop reference values i _dref and i _qref are obtained by the V/f control method, and the specific formula is as follows:

θ=∫(2πf-ω)dt, U _dref =u _ref cosθ, U _qref =u _ref sinθ,

i _dref =K _pv (u _dref -v _d )+K _iv ∫(u _dref -v _d )dt,i _qref =K _pv (u _dref -v _d )+K _iv ∫(u _qref -v _q )dt

Where u _ref is the voltage loop reference value, ω is the rectified inverter output angular frequency, θ is the rectified inverter output voltage phase angle, K _pv is the voltage loop proportional coefficient, and K _iv is the voltage loop integral coefficient;

Step 23: Obtain v _sd and v _{sq according} to the inner loop control method according to i _1d , i _1q , i _2d , i _2q , i _dref , i _qref , v _d , v _q , and the specific formula is as follows:

v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

Step 24: Calculate the abc axis component according to v _sd and v _sq , convert it to PWM and output it to the rectifier inverter.

Further, step 3 specifically includes the following steps:

Step 31: Obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate a dq axis component i _1d , i _{1q thereof} ; obtain a fourth inductance and a rectified inverter output voltage value v, a current value i ₂ between the first resistors and between the fifth inductor and the first resistor, wherein the voltage v includes its abc axis components v _a , v _b , v _c , and then Calculating the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

Step 32: According to v _d , v _q , i _2d , i _2q , P _ref , Q _ref , the current loop reference values i _dref and i _qref are obtained by the P/Q control method, and the specific formula is as follows:

P=v _d i _2d +v _q i _2q ,Q=v _q i _2d +v _d i _2q

i _dref =K _pP (P _ref -P)+K _iP ∫(P _ref -P)dt

i _qref =K _pQ (Q _ref -Q)+K _iQ ∫(Q _ref -Q)dt

Where P _ref is the active power reference value, Q _ref is the reactive power reference value, K _pP is the proportional coefficient of active control, K _pQ is the proportional coefficient of reactive power control, K _iP is the integral coefficient of active control, and K _iQ is Integral coefficient of reactive power control;

Step 33: Obtain v _sd and v _{sq according} to the inner loop control method according to i _1d , i _1q , i _2d , i _2q , i _dref , i _qref , v _d , v _q , and the specific formula is as follows:

v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

Step 24: Input v _sd , v _sq , calculate its abc axis component, convert to PWM and output to the rectifier inverter.

Further, the phase locked loop control method includes the following steps:

Step 61: Obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate a dq axis component i _1d , i _{1q thereof} ; obtain a fourth inductance and a rectified inverter output voltage value v, a current value i ₂ between the first resistors and between the fifth inductor and the first resistor, wherein the voltage v includes its abc axis components v _a , v _b , v _c , and then Calculating the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

Step 62: According to v _a , v _b , v _c , ω _ff , the phase-locked loop output θ _pll is obtained by a phase-locked loop control method, and the specific formula is as follows:

ω _pll =ω _ff +K _p.pll v _q +K _{i.pll ∫v q} dt

Where K _p.pll is the phase-locked loop proportional coefficient, K _i.pll is the phase-locked loop integral coefficient, ω _ff is the theoretical angular frequency, ω _ff =2*π*60Hz, and ω _pll is the rectifier inverter output voltage Angular frequency;

Step 63: Input θ _p11 , and output to the rectifier inverter after processing.

The invention also provides a device for seamlessly switching ship power of 50Hz-60Hz and 50Hz-50Hz dual-frequency shore power, including shore power transformer, rectification inverter, 50Hz line, 60Hz line, public line, inner ring controller and external a ring controller, the outer ring controller includes a V/f controller, a P/Q controller, and a phase locked loop controller;

The shore power transformer, the rectification inverter, the 50 Hz line, and the public line are sequentially connected, the shore power transformer, the rectification inverter, the 60 Hz line, and the public line are sequentially connected, and the 50 Hz or 60 Hz line is selected according to the ship power grid standard; One end is used for connection with the onshore power supply, and the other end of the public line is used for connection with the ship's power grid;

The V/f controller is configured to convert a target frequency of the ship generator into a target frequency output by the shore power transformer;

The P/Q controller is configured to control the frequency and voltage of the ship generator after the V/f controller is processed, and use the real-time load power of the ship power grid as the target power to perform power transfer, and the output power of the rectifier inverter increases. The output power of the ship generator is reduced. When the output power of the ship generator drops to a preset power or below, the ship generator is turned off;

The phase locked loop controller is used to control the frequency and voltage of the rectifier inverter output.

Further, the 50 Hz line includes a first switch, a second switch, a first inductor, a second inductor, a fourth inductor, and a first capacitor, and the 60 Hz line includes a third switch, a third inductor, a fifth inductor, and a a second capacitor, the common line includes a first resistor, a sixth inductor, and a fourth switch;

One end of the shore power transformer is used to connect the shore power source, the other end is connected to one end of the rectifier inverter and the first switch, and the other end of the rectifier inverter is respectively connected to one end of the second switch and the third switch; the other end of the first switch Connecting the first inductor to the other end of the second switch, the other end of the second switch is connected to the first connection end of the second inductor, and the second connection end of the second inductor is connected in series with the fourth inductor, the first resistor, One end of the sixth inductor and the fourth switch, one end of the first capacitor is connected between the second inductor and the fourth inductor, and the other end is grounded; the other end of the third switch is connected to the first connection end of the third inductor, and the third The second connection end of the inductor is connected in series with one end of the fifth inductor, the first resistor, the sixth inductor and the fourth switch, one end of the second capacitor is connected between the third inductor and the fifth inductor, and the other end is grounded; The other end of the four switches is used to connect to the ship's power grid.

Further, an A processor, a B processor, and a rectification inverter processor are further included;

The A processor is configured to obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate dq axis components i _1d , i _{1q thereof} ;

The B processor is configured to obtain a rectified inverter output voltage value v and a current value i ₂ between the fourth inductor and the first resistor and between the fifth inductor and the first resistor, wherein the voltage v includes the abc thereof The axis components v _a , v _b , v _c , then calculate the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

The V/f controller is connected to the B processor, and is configured to obtain V _d and v _q input by the B processor, and obtain current loop reference values i _dref and i _qref according to the V/f control method, and the specific formula is as follows :

θ=∫(2πf-ω)dt, U _dref =u _ref cosθ, U _qref =u _ref sinθ,

i _dref =K _pv (u _dref -v _d )+K _iv ∫(u _dref -v _d )dt,i _qref =K _pv (u _dref -v _d )+K _iv ∫(u _qref -v _q )dt

Where u _ref is the voltage loop reference value, ω is the rectified inverter output angular frequency, θ is the rectified inverter output voltage phase angle, K _pv is the voltage loop proportional coefficient, and K _iv is the voltage loop integral coefficient;

The inner loop controller is respectively connected to the A processor, the B processor and the V/f controller, and is used for obtaining i _1d and i _1q input by the A processor, and i _2d and i _2q input by the B processor. , v _d , v _q , i _dref , i _qref input by the V/f controller, obtain v _sd and v _sq according to the inner loop control method, and the specific formula is as follows:

v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

The rectifier inverter processor is connected to the inner loop controller for obtaining v _sd and v _{sq of the} input of the inner loop controller, calculating the abc axis component thereof, converting to PWM, and outputting to the rectifier inverter.

Further, an A processor, a B processor, and a rectification inverter processor are further included;

The A processor is configured to obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate dq axis components i _1d , i _{1q thereof} ;

The B processor is configured to obtain a rectified inverter output voltage value v and a current value i ₂ between the fourth inductor and the first resistor and between the fifth inductor and the first resistor, wherein the voltage v includes the abc thereof The axis components v _a , v _b , v _c , then calculate the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

The P/Q controller is connected to the B processor for obtaining V _d , v _q , i _2d , i _2q input by the B processor, and obtaining a current loop reference value i _dref according to the P/Q control method, i _qref , the specific formula is as follows:

P=v _d i _2d +v _q i _2q ,Q=v _q i _2d +v _d i _2q

i _dref =K _pP (P _ref -P)+K _iP ∫(P _ref -P)dt

i _qref =K _pQ (Q _ref -Q)+K _iQ ∫(Q _ref -Q)dt

Where P _ref is the active power reference value, Q _ref is the reactive power reference value, K _pP is the proportional coefficient of active control, K _pQ is the proportional coefficient of reactive power control, K _iP is the integral coefficient of active control, and K _iQ is Integral coefficient of reactive power control;

The inner loop controller is respectively connected to the A processor, the B processor, and the P/Q controller, and is used for obtaining i _1d and i _1q input by the A processor, and i _2d and i _2q input by the B processor. , v _d , v _q , i _dref and i _qref input by the P/Q controller, obtain v _sd and v _sq according to the inner loop control method, and the specific formula is as follows:

v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

The rectifier inverter processor is connected to the inner loop controller and the rectifying inverter, and is configured to obtain v _sd and v _{sq of the} input of the inner loop controller, calculate an abc axis component thereof, convert the signal into a PWM, and output the Rectifier inverter.

Further, a rectifier inverter processor is further included;

The phase-locked loop controller is respectively connected between the fourth inductor and the first resistor and between the fifth inductor and the first resistor for obtaining the components v _a , v _b of the voltage v at the abc axis, v _c , according to the phase-locked loop control method to obtain the phase-locked loop output θ _pll , the specific formula is as follows:

ω _pll =ω _ff +K _p.pll v _q +K _{i.pll ∫v q} dt

Where K _p.pll is the phase-locked loop proportional coefficient, K _i.pll is the phase-locked loop integral coefficient, s is, ω _ff is the theoretical angular frequency, ω _ff =2*π*60Hz, and ω _pll is the rectifying inverter The angular frequency of the output voltage;

The rectification inverter processor is connected to the phase-locked loop controller and the rectification inverter for obtaining θ _{p11 of the} input of the phase-locked loop controller, and is processed and transmitted to the rectification inverter.

For a better understanding and implementation, the invention will be described in detail below with reference to the drawings.

DRAWINGS

Figure 1 is a flow chart of the present invention;

FIG. 2 is a schematic diagram of the shore power seamless switching ship of the present invention.

Detailed ways

Please refer to FIG. 1 , which is a flowchart of the present invention. Referring to FIG. 2 , it is a schematic diagram of the shore power seamless switching ship of the present invention. The device for seamlessly switching ship power of 50Hz-60Hz and 50Hz-50Hz dual-frequency shore power according to the present invention is specifically a shore power grid line installed on the shore, which comprises a shore power transformer, a rectification inverter, a 50Hz line, a 60Hz line, The public line and the control line include an inner loop controller and an outer loop controller, and the outer loop controller includes a V/f controller, a P/Q controller, and a phase locked loop controller. In this embodiment, the onshore power supply is made of 400V/50Hz, which can be used for 400V/50Hz ships and 460V/60Hz ships. 50Hz-60Hz means 50Hz shore power and 60Hz ship power docking, 50Hz-50Hz means 50Hz shore power and 50Hz ship power docking.

The shore power transformer T1, the rectifier inverter UI1, the 50Hz line, and the public line are sequentially connected, the shore power transformer T1, the rectifier inverter UI1, the 60Hz line, and the public line are sequentially connected, and the 50Hz or 60Hz line is selected according to the ship power grid standard; The other end of the shore power transformer is used to connect to the onshore power supply, and the other end of the public line is used to connect to the ship's power grid.

Specifically, the 50 Hz line includes a first switch K1, a second switch K2, a first inductor L1, a second inductor L2, a fourth inductor L4, and a first capacitor C1. The 60 Hz line includes a third switch K3 and a third The inductor L3, the fifth inductor L5 and the second capacitor C2, the common circuit includes a first resistor R1, a sixth inductor L6 and a fourth switch K4; one end of the shore transformer T1 is used for connecting the shore power supply, and the other end is respectively connected to the rectifier One end of the inverter UI1, the first switch K1, and the other end of the rectifying inverter UI1 are respectively connected to one ends of the second switch K2 and the third switch K3; the other end of the first switch K1 is connected in series with the first inductor L1, and then connected The other end of the second switch K2 is connected to the first end of the second inductor L2, and the second end of the second inductor L2 is connected in series with the fourth inductor L4, the first resistor R1, and the sixth One end of the inductor L6 and the fourth switch K4, one end of the first capacitor C1 is connected between the second inductor L2 and the fourth inductor L4, and the other end thereof is grounded; the other end of the third switch K3 is connected to the first of the third inductor L3 a second end of the third inductor L3 is connected in series with the fifth inductor L5, One end of the resistor R1, the sixth inductor L6 and the fourth switch K4, one end of the second capacitor C2 is connected between the third inductor L3 and the fifth inductor L5, and the other end thereof is grounded; the other end of the fourth switch K4 is used for Connected to the ship's power grid. The first resistor R1 and the sixth inductor L6 are used for current limiting, and may be omitted in other embodiments.

The method for seamlessly switching the shipboard power of the 50Hz-60Hz and 50Hz-50Hz dual-frequency shore power of the invention comprises the following steps:

Step 1: Connect the shore power grid lines to the shore power source and the ship grid respectively, specifically connect the shore power transformer to the shore power supply, and connect the other end of the public line to the ship power grid; the shore power grid line is selected according to the ship power grid standard. 50Hz or 60Hz line; if the ship grid standard is 50Hz, select the 50Hz line to close the second switch and the fourth switch; if the ship grid standard is 60Hz, select the 60Hz line to close the third switch and the fourth switch.

Step 2: The rectifier inverter adopts the inner loop control method and the outer loop control method. In this step 2, the outer loop control method adopts the V/f control method, and the target frequency of the ship generator is converted into the target of the shore power transformer output. Frequency; at the same time, with the phase-locked loop control method to stabilize the frequency and voltage.

According to the V/f control theory of rectifier inverter, V/f control consists of current inner loop and voltage outer loop. The main coefficients are: current loop proportional coefficient K _pi and integral coefficient K _ii , voltage loop proportional coefficient K _pv and integral The coefficient K _iv , the load equivalent resistance R, the equivalent reactance X, the filter inductor L _s , the rectifier inverter output current excluding the capacitance filter I ₁ ≈I ₂ ≈I, I _d , I _q are the dq axis components, respectively.

Let the dq axis components U _dref and U _qref of the reference value U _ref of the voltage loop be the input, and the dq axis components V _d and V _q of the rectifier inverter output voltage be the output, and the system equation is the following formula:

Specifically, in the present invention, step 2 includes the following steps:

Step 21: Set A point at the second connection end of the second inductor and the second connection end of the third inductor, obtain a rectified inverter output current value i ₁ at point A, and calculate a dq axis component i _{1d thereof} , i _1q ; a point B is set between the fourth inductor and the first resistor and between the fifth inductor and the first resistor, and a rectified inverter output voltage value v and a current value i ₂ at point B are obtained, wherein the voltage v Including its abc axis components v _a , v _b , v _c , and then calculating the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

Step 22: Input ω, u _ref , v _d , v _q , and obtain current loop reference values i _dref and i _qref according to the V/f control method. The specific formula is as follows:

θ=∫(2πf-ω)dt, U _dref =u _ref cosθ, U _qref =u _ref sinθ,

i _dref =K _pv (u _dref -v _d )+K _iv ∫(u _dref -v _d )dt,i _qref =K _pv (u _dref -v _d )+K _iv ∫(u _qref -v _q )dt

Where u _ref is the reference value of the voltage loop, according to the voltage setting of the ship grid, ω is the output angular frequency of the rectifier inverter, that is, the voltage frequency of the ship grid is 60 Hz, θ is the phase angle of the output voltage of the rectifier inverter, K _pv is Voltage loop proportional coefficient, K _iv is the voltage loop integral coefficient;

Step 23: Input i _1d , i _1q , i _2d , i _2q , i _dref , i _qref , v _d , v _q , and obtain v _sd and v _sq according to the inner loop control method. The specific formula is as follows:

v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

Step 24: Input v _sd , v _sq , calculate its abc axis component, convert to PWM and output to the rectifier inverter.

In one embodiment, phase-lock loop control is performed while step 2 is being performed to stabilize the frequency and voltage.

According to the theory of phase-locked loop control, when the frequency of the input quantity changes, the output of the three-phase phase-locked loop is still the same output signal as the input frequency, and there are DC offset, three-phase asymmetry, harmonic distortion, etc. at the input. Under the condition, the three-phase phase-locked loop has better anti-interference ability. Refer to the following formula, where θ is the phase angle of the rectified inverter output voltage, θ _pll is the phase-locked loop output, and ω _ff and θ _ff are the target values:

v _q =Vsin(θ-θ _pll )

θ=ω ₀ t+θ ₀

That is, at the same time as step 2 of the present invention, the following step 6 is performed simultaneously:

Step 61: Set A point at the second connection end of the second inductor and the second connection end of the third inductor, obtain a rectified inverter output current value i ₁ at point A, and calculate a dq axis component i _{1d thereof} , i _1q ; a point B is set between the fourth inductor and the first resistor and between the fifth inductor and the first resistor, and a rectified inverter output voltage value v and a current value i ₂ at point B are obtained, wherein the voltage v Including its abc axis components v _a , v _b , v _c , and then calculating the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

Step 62: Input v _a , v _b , v _c , ω _ff , and obtain the phase-locked loop output θ _pll according to the phase-locked loop control method. The specific formula is as follows:

ω _pll =ω _ff +K _p.pll v _q +K _{i.pll ∫v q} dt

Where K _p.pll is the phase-locked loop proportional coefficient, K _i.pll is the phase-locked loop integral coefficient, ω _ff is the theoretical angular frequency, ω _ff =2*π*60Hz; ω _pll is the rectifier inverter output voltage Angular frequency;

Step 63: Input θ _p11 , and output to the rectifier inverter after processing.

The phase-locked loop control method of step 6 can stabilize the output frequency and voltage of the rectifier inverter.

Step 3: The outer loop control method of the rectifier inverter is converted from the V/f control method to the P/Q control method to control the ship generator frequency and voltage, and the ship power grid real-time load power is used as the target power for power transfer and rectification. The output power of the inverter is gradually increased, and the output power of the ship generator is gradually decreased. At the same time, the phase-locked loop control method is used to stabilize the frequency and voltage. In this process, the ship generator can reduce the load by droop control, automatic frequency modulation or manual adjustment of the governor.

According to the P/Q control theory of the rectified inverter, the P/Q control realizes the maximum utilization of the intermittent power supply in the microgrid, and the output active and reactive power are their reference values P _ref and Q _{ref , respectively} . The control principle is: the power reference value is subtracted from the measured value, and the current reference signal i _dref , i _{qref is} obtained after the proportional integral controller, thereby controlling the output power of the rectifying inverter, the proportional coefficient K _{pP of the} P/Q control and The integral coefficient K _iP , refer to the following formula:

P _ref =K _P/f (f _ref -f)

Q _ref =K _Q/f (U _ref -U)

Specifically, in the present invention, step 3 includes the following steps:

Step 31: Set A point at the second connection end of the second inductor and the second connection end of the third inductor, obtain a rectified inverter output current value i ₁ at point A, and calculate a dq axis component i _{1d thereof} , i _1q ; a point B is set between the fourth inductor and the first resistor and between the fifth inductor and the first resistor, and a rectified inverter output voltage value v and a current value i ₂ at point B are obtained, wherein the voltage v Including its abc axis components v _a , v _b , v _c , and then calculating the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

Step 32: Input v _d , v _q , i _2d , i _2q , P _ref , Q _ref , and obtain current loop reference values i _dref and i _qref according to the P/Q control method. The specific formula is as follows:

P=v _d i _2d +v _q i _2q ,Q=v _q i _2d +v _d i _2q

i _dref =K _pP (P _ref -P)+K _iP ∫(P _ref -P)dt

i _qref =K _pQ (Q _ref -Q)+K _iQ ∫(Q _ref -Q)dt

Where P _ref is the active power reference value, Q _ref is the reactive power reference value, K _pP is the proportional coefficient of active control, K _pQ is the proportional coefficient of reactive power control, K _iP is the integral coefficient of active control, and K _iQ is Integral coefficient of reactive power control;

Step 33: Input i _1d , i _1q , i _2d , i _2q , i _dref , i _qref , v _d , v _q , and obtain v _sd and v _sq according to the inner loop control method. The specific formula is as follows:

v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

Step 34: Input v _sd , v _sq , calculate its abc axis component, convert to PWM and output to the rectifier inverter.

At the same time as step 3, phase-locked loop control is performed to stabilize the frequency and voltage, that is, step 6 is performed simultaneously, and step 6 has been explained above, and will not be described again.

Step 4: When the ship generator output power drops to the preset power, the ship generator is turned off and the power supply seamless switching is completed. Specifically, the rated power of the ship generator with a preset power of 5% may also be set to other sizes depending on the situation.

Step 5: If the ship's power grid standard is 50Hz, that is, both the ship's power and the shore power are 400V/50Hz, the rectifier inverter is not required for voltage transformation and frequency modulation. At this time, the rectifier inverter can be bypassed by the shore power transformer. Direct power supply to save energy, specifically to close the first switch; if the ship's power grid standard is 60Hz, then this step is not performed, that is, step 4 has completed the operation.

When the ship needs to be offshore, take the reverse operation of the above steps: first start the ship generator, connect the generator to the shore power grid line, then transfer the load power of the on-board rectifier inverter to the ship generator, and add and subtract throttle on the ship. Operation, when the load power of the on-shore rectifier inverter is reduced to 5% of rated power or less (at this time, the current is small), the shore power grid line is disconnected from the ship grid, and the power supply is seamlessly switched.

Ships connected to shore power can achieve ship energy conservation and port emission reduction and environmental protection. Take a ferry between Poland and Sweden in 2012 as an example. It stops at the Polish port for 3 hours every day and stops at the Swedish port for 7 hours. Relative to the cost of power generation/shore power, Sweden and Poland are 724/356 US dollars and 1759/678 US dollars respectively. Save $1,449 per day with shore power. The consultation report of MariTerm AB pointed out that the indirect cost of heavy diesel emissions and noise from shipbuilding power generation in EU countries is more than 10 times the direct cost. If 80% of China's ports are connected to shore power by port, the annual energy-saving economic benefits can reach more than 1.9 billion yuan, and the social benefits of port environmental protection are more significant.

The method and device for seamlessly switching ship power of 50Hz-60Hz and 50Hz-50Hz dual-frequency shore power according to the present invention, when the shore power and the ship power supply are switched, the shipboard equipment does not need to be powered off, and the frequency f is controlled by V/f control, and then Through P/Q control, the load power is transferred from the ship generator to the shore power grid to complete seamless switching. In addition, the shore power 50Hz power supply can be realized, and the ships of different grid standards of 60Hz or 50Hz can be powered to adapt to different ships. The need, when the 50Hz ship is seamlessly connected to the shore, without the need of a traditional synchronous meter or current limiting control, a 60Hz rectifying inverter is used as a 50Hz seamless smoothing shore electrical transition device. After the switching is completed, the rectification inverse is turned off. The transformer is switched from 50Hz inverter power supply to shore power transformer for direct power supply, achieving smooth connection without inrush current.

The above-described embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims (10)

1. A method for seamlessly switching ship power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power, characterized in that the method comprises the following steps:

   Step 1: Connect the shore power grid lines including the shore power transformer and the rectifier inverter to the shore power source and the ship grid respectively, and select the shore power grid line as a 50 Hz or 60 Hz line according to the ship grid standard;

   Step 2: The inner loop control method and the outer loop control method are adopted for the rectifier inverter, wherein the outer loop control method adopts the V/f control method, and the target frequency of the ship generator is converted into the target frequency of the shore power transformer output; Using a phase-locked loop control method to control the frequency and voltage of the rectifier inverter output;

   Step 3: Convert the outer loop control method of the rectifier inverter from the V/f control method to the P/Q control method, control the ship generator frequency and voltage, and use the ship grid real-time load power as the target power to perform power transfer. The output power of the rectifier inverter increases, and the output power of the ship generator decreases; meanwhile, the phase-locked loop control method is used to control the frequency and voltage of the rectifier inverter output;

   Step 4: When the ship generator output power drops to the preset power, the ship generator is turned off.
2. The method for seamlessly switching a shipboard power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power according to claim 1, wherein the shore power grid line comprises a shore power transformer, a rectification inverter, a 50 Hz line, and a 60 Hz line. a line and a public line, the 50 Hz line includes a first switch, a second switch, a first inductor, a second inductor, a fourth inductor, and a first capacitor, and the 60 Hz line includes a third switch, a third inductor, and a fifth inductor And a second capacitor, the common line including a first resistor, a sixth inductor, and a fourth switch;

   One end of the shore power transformer is used to connect the shore power source, the other end is connected to one end of the rectifier inverter and the first switch, and the other end of the rectifier inverter is respectively connected to one end of the second switch and the third switch; the other end of the first switch Connecting the first inductor to the other end of the second switch, the other end of the second switch is connected to the first connection end of the second inductor, and the second connection end of the second inductor is connected in series with the fourth inductor, the first resistor, a sixth inductor and a fourth switch are connected to the ship grid through the fourth switch, one end of the first capacitor is connected between the second inductor and the fourth inductor, and the other end is grounded; the other end of the third switch is connected to the third a first connection end of the inductor, a second connection end of the third inductor is sequentially connected in series with one ends of the fifth inductor, the first resistor, the sixth inductor and the fourth switch, and one end of the second capacitor is connected to the third inductor and the fifth inductor Between the other end of it is grounded.
3. The method for seamlessly switching a shipboard power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power according to claim 2, wherein the step 2 specifically comprises the following steps:

   Step 21: Obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate a dq axis component i _1d , i _{1q thereof} ; obtain a fourth inductance and a rectified inverter output voltage value v, a current value i ₂ between the first resistors and between the fifth inductor and the first resistor, wherein the voltage v includes its abc axis components v _a , v _b , v _c , and the calculation current The dq axis components i _2d , i _{2q of the} value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

   Step 22: According to ω, u _ref , v _d , v _q , the current loop reference values i _dref and i _qref are obtained by the V/f control method, and the specific formula is as follows:

   θ=∫(2πf-ω)dt, U _dref =u _ref cosθ, U _qref =u _ref sinθ,

   i _dref =K _pv (u _dref -v _d )+K _iv ∫(u _dref -v _d )dt,i _qref =K _pv (u _dref -v _d )+K _iv ∫(u _qref -v _q )dt

   Where u _ref is the voltage loop reference value, ω is the rectified inverter output angular frequency, θ is the rectified inverter output voltage phase angle, K _pv is the voltage loop proportional coefficient, and K _iv is the voltage loop integral coefficient;

   Step 23: Obtain v _sd and v _{sq according} to the inner loop control method according to i _1d , i _1q , i _2d , i _2q , i _dref , i _qref , v _d , v _q , and the specific formula is as follows:

   v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

   v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

   Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

   Step 24: Calculate the abc axis component according to v _sd and v _sq , convert it to PWM and output it to the rectifier inverter.
4. The method for seamlessly switching a shipboard power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power according to any one of claims 2 or 3, wherein the step 3 specifically comprises the following steps:

   Step 31: Obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate a dq axis component i _1d , i _{1q thereof} ; obtain a fourth inductance and a rectified inverter output voltage value v, a current value i ₂ between the first resistors and between the fifth inductor and the first resistor, wherein the voltage v includes its abc axis components v _a , v _b , v _c , and then Calculating the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

   Step 32: According to v _d , v _q , i _2d , i _2q , P _ref , Q _ref , the current loop reference values i _dref and i _qref are obtained by the P/Q control method, and the specific formula is as follows:

   P=v _d i _2d +v _q i _2q ,Q=v _q i _2d +v _d i _2q

   i _dref =K _pP (P _ref -P)+K _iP ∫(P _ref -P)dt

   i _qref =K _pQ (Q _ref -Q)+K _iQ ∫(Q _ref -Q)dt

   Where P _ref is the active power reference value, Q _ref is the reactive power reference value, K _pP is the proportional coefficient of active control, K _pQ is the proportional coefficient of reactive power control, K _iP is the integral coefficient of active control, and K _iQ is Integral coefficient of reactive power control;

   Step 33: Obtain v _sd and v _{sq according} to the inner loop control method according to i _1d , i _1q , i _2d , i _2q , i _dref , i _qref , v _d , v _q , and the specific formula is as follows:

   v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

   v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

   Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

   Step 24: Input v _sd , v _sq , calculate its abc axis component, convert to PWM and output to the rectifier inverter.
5. The method for seamlessly switching a shipboard power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power according to any one of claims 2 or 3, wherein the phase-locked loop control method comprises the following steps:

   Step 61: Obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate a dq axis component i _1d , i _{1q thereof} ; obtain a fourth inductance and a rectified inverter output voltage value v, a current value i ₂ between the first resistors and between the fifth inductor and the first resistor, wherein the voltage v includes its abc axis components v _a , v _b , v _c , and then Calculating the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

   Step 62: According to v _a , v _b , v _c , ω _ff , the phase-locked loop output θ _pll is obtained by a phase-locked loop control method, and the specific formula is as follows:

   

   ω _pll =ω _ff +K _p.pll v _q +K _{i.pll ∫v q} dt

   Where K _p.pll is the phase-locked loop proportional coefficient, K _i.pll is the phase-locked loop integral coefficient, ω _ff is the theoretical angular frequency, ω _ff =2*π*60Hz, and ω _pll is the rectifier inverter output voltage Angular frequency;

   Step 63: Input θ _p11 , and output to the rectifier inverter after processing.
6. A device for seamlessly switching ship power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power, comprising: shore power transformer, rectification inverter, 50 Hz line, 60 Hz line, public line, inner ring controller and external a ring controller, the outer ring controller includes a V/f controller, a P/Q controller, and a phase locked loop controller;

   The shore power transformer, the rectification inverter, the 50 Hz line, and the public line are sequentially connected, the shore power transformer, the rectification inverter, the 60 Hz line, and the public line are sequentially connected, and the 50 Hz or 60 Hz line is selected according to the ship power grid standard; One end is used for connection with the onshore power supply, and the other end of the public line is used for connection with the ship's power grid;

   The V/f controller is configured to convert a target frequency of the ship generator into a target frequency output by the shore power transformer;

   The P/Q controller is configured to control the frequency and voltage of the ship generator after the V/f controller is processed, and use the real-time load power of the ship power grid as the target power to perform power transfer, and the output power of the rectifier inverter increases. The output power of the ship generator is reduced. When the output power of the ship generator drops to a preset power or below, the ship generator is turned off;

   The phase locked loop controller is used to control the frequency and voltage of the rectifier inverter output.
7. The device for seamlessly switching between 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power according to claim 6, wherein the 50 Hz line comprises a first switch, a second switch, a first inductor, and a second inductor. a fourth inductor and a first capacitor, the 60 Hz line includes a third switch, a third inductor, a fifth inductor, and a second capacitor, the common line including a first resistor, a sixth inductor, and a fourth switch;

   One end of the shore power transformer is used to connect the shore power source, the other end is connected to one end of the rectifier inverter and the first switch, and the other end of the rectifier inverter is respectively connected to one end of the second switch and the third switch; the other end of the first switch Connecting the first inductor to the other end of the second switch, the other end of the second switch is connected to the first connection end of the second inductor, and the second connection end of the second inductor is connected in series with the fourth inductor, the first resistor, One end of the sixth inductor and the fourth switch, one end of the first capacitor is connected between the second inductor and the fourth inductor, and the other end is grounded; the other end of the third switch is connected to the first connection end of the third inductor, and the third The second connection end of the inductor is connected in series with one end of the fifth inductor, the first resistor, the sixth inductor and the fourth switch, one end of the second capacitor is connected between the third inductor and the fifth inductor, and the other end is grounded; The other end of the four switches is used to connect to the ship's power grid.
8. The apparatus for seamlessly switching a shipboard power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power according to claim 7, further comprising: an A processor, a B processor, and a rectification inverter processor;

   The A processor is configured to obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate dq axis components i _1d , i _{1q thereof} ;

   The B processor is configured to obtain a rectified inverter output voltage value v and a current value i ₂ between the fourth inductor and the first resistor and between the fifth inductor and the first resistor, wherein the voltage v includes the abc thereof The axis components v _a , v _b , v _c , then calculate the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

   The V/f controller is connected to the B processor, and is configured to obtain V _d and v _q input by the B processor, and obtain current loop reference values i _dref and i _qref according to the V/f control method, and the specific formula is as follows :

   θ=∫(2πf-ω)dt, U _dref =u _ref cosθ, U _qref =u _ref sinθ,

   i _dref =K _pv (u _dref -v _d )+K _iv ∫(u _dref -v _d )dt,i _qref =K _pv (u _dref -v _d )+K _iv ∫(u _qref -v _q )dt

   Where u _ref is the voltage loop reference value, ω is the rectified inverter output angular frequency, θ is the rectified inverter output voltage phase angle, K _pv is the voltage loop proportional coefficient, and K _iv is the voltage loop integral coefficient;

   The inner loop controller is respectively connected to the A processor, the B processor and the V/f controller, and is used for obtaining i _1d and i _1q input by the A processor, and i _2d and i _2q input by the B processor. , v _d , v _q , i _dref , i _qref input by the V/f controller, obtain v _sd and v _sq according to the inner loop control method, and the specific formula is as follows:

   v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

   v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

   Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

   The rectifier inverter processor is connected to the inner loop controller for obtaining v _sd and v _{sq of the} input of the inner loop controller, calculating the abc axis component thereof, converting to PWM, and outputting to the rectifier inverter.
9. The apparatus for seamlessly switching ship power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power according to any one of claims 7 or 8, characterized in that it further comprises an A processor, a B processor and a rectification inverter processor;

   The A processor is configured to obtain a rectified inverter output current value i ₁ at a second connection end of the second inductor and a second connection end of the third inductor, and calculate dq axis components i _1d , i _{1q thereof} ;

   The B processor is configured to obtain a rectified inverter output voltage value v and a current value i ₂ between the fourth inductor and the first resistor and between the fifth inductor and the first resistor, wherein the voltage v includes the abc thereof The axis components v _a , v _b , v _c , then calculate the dq axis components i _2d , i _{2q of the} current value i ₂ , and the dq axis components v _d , v _{q of the} voltage;

   The P/Q controller is connected to the B processor for obtaining V _d , v _q , i _2d , i _2q input by the B processor, and obtaining a current loop reference value i _dref according to the P/Q control method, i _qref , the specific formula is as follows:

   P=v _d i _2d +v _q i _2q ,Q=v _q i _2d +v _d i _2q

   i _dref =K _pP (P _ref -P)+K _iP ∫(P _ref -P)dt

   i _qref =K _pQ (Q _ref -Q)+K _iQ ∫(Q _ref -Q)dt

   Where P _ref is the active power reference value, Q _ref is the reactive power reference value, K _pP is the proportional coefficient of active control, K _pQ is the proportional coefficient of reactive power control, K _iP is the integral coefficient of active control, and K _iQ is Integral coefficient of reactive power control;

   The inner loop controller is respectively connected to the A processor, the B processor, and the P/Q controller, and is used for obtaining i _1d and i _1q input by the A processor, and i _2d and i _2q input by the B processor. , v _d , v _q , i _dref and i _qref input by the P/Q controller, obtain v _sd and v _sq according to the inner loop control method, and the specific formula is as follows:

   v _sd =v _d -ωL _s i _lq +K _pi (i _dref -i _2d )+K _ii ∫(i _dref -i _2d )dt

   v _sq =v _q -ωL _s i _lq +K _pi (i _qref -i _2q )+K _ii ∫(i _qref -i _2q )dt;

   Where K _pi is the current loop proportional coefficient, K _ii is the current loop integral coefficient, and L _s is the filter inductor;

   The rectifier inverter processor is connected to the inner loop controller and the rectifying inverter, and is configured to obtain v _sd and v _{sq of the} input of the inner loop controller, calculate an abc axis component thereof, convert the signal into a PWM, and output the Rectifier inverter.
10. The apparatus for seamlessly switching a shipboard power of 50 Hz-60 Hz and 50 Hz-50 Hz dual-frequency shore power according to any one of claims 7 or 8, further comprising: a rectifying inverter processor;

    The phase-locked loop controller is connected between the fourth inductor and the first resistor and between the fifth inductor and the first resistor, respectively, for obtaining the components v _a , v _b of the voltage v at the abc axis. v _c , according to the phase-locked loop control method to obtain the phase-locked loop output θ _pll , the specific formula is as follows:

    

    ω _pll =ω _ff +K _p.pll v _q +K _{i.pll ∫v q} dt

    Where K _p.pll is the phase-locked loop proportional coefficient, K _i.pll is the phase-locked loop integral coefficient, ω _ff is the theoretical angular frequency, ω _ff =2*π*60Hz, and ω _pll is the rectifier inverter output voltage Angular frequency;

    The rectification inverter processor is connected to the phase-locked loop controller and the rectification inverter for obtaining θ _{p11 of the} input of the phase-locked loop controller, and is processed and transmitted to the rectification inverter.

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